This research program concerns studies of the chemical nature of intermediates in the biosynthesis of cholesterol; studies of the mechanism and stereochemistry of individual enzymatic reactions involved in the biosynthesis of cholesterol, sphingolipids, fatty acids, and related compounds; studies of the chemistry, metabolism, and enzymology of sphingolipid bases and their derivatives; fundamental studies relative to the regulation of sterol synthesis in animal and human cells; fundamental studies of the chemical, nuclear magnetic resonance, and mass spectral properties of sterols and sphingolipids; and applications of mass spectrometry to the solution of biochemical problems.